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arXiv 1910.02232math.NAcs.NA
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一个倒向抛物型方程的分式算子正则化

Regularization of a backwards parabolic equation by fractional operators

Barbara Kaltenbacher, William Rundell

摘要:

后向扩散方程是一类经典的不适定反问题,有着广泛的应用,近50年来得到了广泛的研究。第一个方法之一是{ \it quasireversibility\/},其中抛物算子被替换为一个微分算子,其中向后的问题在时间上是很好的。这实际上是我们将采取的方向,但将使用非局部算子;分数阶时间方程,已知向后问题是“几乎适定的”。我们将研究各种可能的选择和策略,但我们的结论是,最好的将利用问题的线性将反演分解为不同的频带,并为每个频带使用不同的分数阶。假设我们对数据中的噪声水平有一个估计,将使用差异原理选择分数指数。分析的方法提供了一些说明性的数值例子。

英文摘要:

The backwards diffusion equation is one of the classical ill-posed inverse problems, related to a wide range of applications, and has been extensively studied over the last 50 years. One of the first methods was that of {\it quasireversibility\/} whereby the parabolic operator is replaced by a differential operator for which the backwards problem in time is well posed. This is in fact the direction we will take but will do so with a nonlocal operator; an equation of fractional order in time for which the backwards problem is known to be ``almost well posed.'' We shall look at various possible options and strategies but our conclusion for the best of these will exploit the linearity of the problem to break the inversion into distinct frequency bands and to use a different fractional order for each. The fractional exponents will be chosen using the discrepancy principle under the assumption we have an estimate of the noise level in the data. An analysis of the method is provided as are some illustrative numerical examples.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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